1. Field of the Invention
The invention concerns a device for x-ray brachytherapy as well as a method for positioning of a probe inserted into the inside of a body for x-ray brachytherapy.
2. Description of the Prior Art
X-ray brachytherapy is a therapeutic treatment with x-rays in which the x-ray source is brought very close to the tissue to be treated (for example a tumor or a vessel wall) after the implementation of a endovascular dilatation. In order to able to insert the x-ray source with the aid of a catheter or a probe either without an invasive procedure or with an optimally minimally-invasive procedure inside a body, a miniaturized x-ray source, is required, as is known from U.S. Pat. No. 6,721,392, for example. This is arranged at the distal end of a probe that, for example, is intraoperatively positioned in a tumor or tumor bed (after its extraction), as is explained in detail in the PR information of Carl Zeiss AG, Medical Engineering Innovation by Carl Zeiss AG, “Intraoperative Strahlentherapie mit dem INTRABEAM System von der Carl Zeiss AG” state as of, September 2004, for example.
A miniaturized x-ray source that is arranged in a catheter with which it can be inserted into the body cavities (lumen) in order to irradiate selected tissue zones from the immediate surroundings from there is known from United States Patent Application Publication 2003/0149327 A1. It contains a shielding rotatable around the axis of the catheter in order to radiate the x-rays in a targeted manner at least perpendicular to the axis in a selected solid angle. The surroundings of the catheter can be observed with an optical observation device arranged in a catheter. A light source that exposes only the part of the surface of the hollow space that is also irradiated is used for this purpose.
Given endovascular brachytherapy with a beta or gamma radiator arranged in the tip of a catheter, it is also known from DE 10 2004 008 373 B3 (for example) to arrange an optical observation device in the catheter. For this a brachytherapy catheter is integrated into a unit with an OCT catheter operating on the basis of optical coherence tomography (OCT).
For the therapeutic success it is essential that the x-rays radiating out of the catheter from the x-ray source in an exposure area for most part exclusively strike the tissue (for example the tumor) to be treated in order to ensure an optimally low exposure of the healthy tissue located near this. This requires a precise positioning of the exposure area, i.e. a precise positioning and alignment of the x-ray source or of the solid angle in which the x-rays exit.